[Spooks] HF Jamming

[Thomas A. Adams]

Not really too sure which list to send this to, so going with WUN and =

SPOOKS mail lists.

On the (local) evening of 26 June 02, (aprox. 0400 - 0500 UTC
of 27 June), I was doing some BCB DXing, and was rather astonished =

to hear AM broadcast staions being jammed...   ALL of them above
1000 KHz! Upon investigation, I discovered that nearly EVERY signal
I could hear at this location up to aprox. 4500 KHz was also being
subjected to jamming! =


The jamming was discreet signals; i.e., not a broadband signal. It
was specifically targeted at any and all radio emissions, and did not
appear in unused spectrum between signals.

The jamming appears to have been SSB signals modulated with a
sound that I can only describe as similar to the sound effects from a =

1950's science fiction movie. The closest I can describe it is like the
sound of a movie ray gun. The jamming signals would go on for about
one minute, and then break for 5 - 10 seconds, as if the source was =

checking it's jamming effectiveness, or looking for new signals to hit
before resuming.

EVERYTHING got hit; WWV @ 2500 KHz was nailed, numerous RTTY
stations, and (rather illogically) the 75 meter ham band! That was =

interesting; numerous ham stations changed frequency to avoid the noise,
and were promptly followed by the jamming to the new frequencies. The
signal also appeared on the 2182 KHz marine calling / distress frequency,=

and on any other signal in the range.

On at least one other occasion I've heard this sort of jamming, but I've
never before heard it extend as low as the AM broadcast band.

Tho the local noise level was sort of high on the AM band, I used my loop=
,
unreliable as it is on skywave signals, to take rough bearings on the
jammers observed in the broadcast band. Propagation was showing an
opening to the Carribean (I'd just logged an AM station on Antigua), and
that's the area where the loop showed nulls on the jammer; i.e., to the
southeast of my Wisconsin location.

A friend of mine reports that he observed similar jamming on the 80 meter=

ham band on Monday evening, and more of it (tho much weaker) on the
160 meter ham band later in the evening.

I'd appreciate hearing from anyone else who may have observed this stuff,=

and while I have my own opinions on sources I'd like to hear what others
think
about it.

73's,

Tom, W9LBB